The present disclosure relates to a bearing that fits and is removable and/or securable to a wall of a reproduction apparatus. The features of the present disclosure provide in embodiments a mounting system advantageously for use in most any apparatus which requires bearings, for example, electrophotographic printing machines.
Electrophotographic marking is a well-known, commonly used method of copying or printing documents. Electrophotographic marking is performed by exposing a charged photoreceptor with a light image representation of a desired document. The photoreceptor is discharged in response to that light image, creating an electrostatic latent image of the desired document on the photoreceptor's surface. Toner particles are then deposited onto that latent image, forming a toner image, which is then transferred onto a substrate, such as a sheet of paper. The transferred toner image is then fused to the substrate, usually using heat and/or pressure, thereby creating a permanent record of the original representation. The surface of the photoreceptor is then cleaned of residual developing material and recharged in preparation for the production of other images. Other marking technologies, for example, electrostatographic marking and ionography are also well-known.
An electrophotographic marking machine generally includes bearings for supporting and connecting parts, for example, auger shafts or developer paddles passing through the housing. The bearings should be able to avoid wear and to minimize resistance, while at the same time having the capacity to seal a hole in the housing which may have a large tolerance variation. As an example, an upper limit of the fit tolerance for a nominal diameter of 16 millimeters due to manufacturing conditions is 300 microns.
The bearings should also provide sealing capacity to prevent contamination of the machine with toner. Average dimension of some toner particles is on the magnitude of 6 microns. Other particles, for example, ferric particulates can be on the magnitude of 60 microns which can result in higher wear of moving parts due to abrasion by the component to the toner carrier material and shortening the lifespan of the developer.
To reduce failure rate and improve performance an extra operation of bonding bearings with adhesives was introduced. This increases the cost of manufacturing and also introduces risk factors associated with adhesives and the possibility of contamination of the inner surface of the bearing.
Other solutions, such as beam support circumferentially distributed around the bearing, are inappropriate for environments involving contaminants, as these require a full through hole to allow for large tolerances, thus allowing transport of contaminant across the bearing. Sealing one face only reduces the capacity of the bearing to deal with the large variation between the shaft and support hole and also limits the degree of dimensional variability with which it can accommodate.
It is therefore desirable to provide a bearing which can be utilized in a wall while still providing generally high durability, minimizing frictional resistance, and maximizing sealing capacity.
Reference is made to the following United States patents relating to reproduction machines and components such as bearings briefly summarized as follows:
U.S. Pat. No. 6,024,497 relates to a bushing mountable in a housing for supporting a rotating member and for providing a bias force to the rotating member. The bushing includes a body defining an aperture therein and a mounting member for mounting the bushing to the housing. The bushing also includes a biasing member operably associated with said body and said mounting member.
U.S. Pat. No. 5,632,684 relates to a shaft assembly and method of forming a shaft assembly having an elongated hollow shaft with a stepped portion on the surface of the shaft. The stepped portion of the shaft surface is formed of two straight edge sections joined by an inclined section. A gear having a corresponding straight/inclined edge configuration engages the shaft and contacts the shaft only on the corresponding straight edge portions.
U.S. Pat. No. 5,538,475 relates to a shaft assembly comprising an elongated member having at least a portion which is hollow, tubular, shell like having an inside surface defining a shaft core and an outside surface defining a shaft functional surface, the shaft core being filled with a hardened, moldable material, and the shaft functional surface having at least one functional feature thereon, which is of hardened, moldable material integrally molded with the hardened, moldable material in the shaft core. U.S. Pat. No. 5,511,885 relates to a plain flanged bearing or bushing for supporting a rotating shaft in a thin walled frame of an electrophotographic printing machine. The composite bearing has a flanged end and is adapted to be inserted in an opening in a thin walled support member until the flange abuts the surface of the wall. A protruding tab formed by displacing a small portion of the flange extends in an axial direction along the bearing and cooperates with a corresponding opening in the wall to prevent rotation of the bearing. A friction push nut or snap ring is attached to the bearing on the side of the wall opposite the flange. The protruding tab prevents the bearing from rotating about an axis which can cause the bearing to be worn on the exterior surface by rotational contact with the thin wall. A shaft to support idler rolls or other rotating elements is inserted in an inner bore of the bearing and is rotatably supported thereby.
U.S. Pat. No. 5,457,520 relates to a bearing for supporting a moving member on a support structure. The bearing includes a substantially U-shaped member having an internal periphery and an external periphery. The bearing also includes a first securer, associated with the internal periphery of the U-shaped member, for securing the moving member to the U-shaped member and a second securer, associated with the external periphery of the U-shaped member, for securing the U-shaped member to the support structure.
U.S. Pat. No. 4,804,277 relates to a bearing mounting system for mounting and retaining a rotatable shaft between first and second bearings mounted to first and second spaced frame members of a machine frame, utilizing commercially available bearings, with respective inner and outer races. Both bearings inner races are press fitted onto the shaft.
U.S. Pat. No. 4,134,175 relates to a non-rotating sleeve type bushing in which an eccentric flange integral with the bushing and projecting radially outwardly therefrom is so formed as to be received in a complementarily contoured flange recess in a bearing housing whereby rotation of the bushing with respect to the bearing housing is precluded by a positive mechanical locking action provided by the shear resistance of the flange member.
U.S. Pat. No. 6,467,965 relates to a bearing for use in reproduction machines that fits and is removable and/or securable to a wall of a reproduction apparatus. The bearing provides a snap-fit mounting feature.
All documents cited herein, including the foregoing, are incorporated herein by reference in their entireties.